From the British Pat. No. 486,985, a seat cushion for such a chair or armchair is already known. From each cushion element of this seat cushion a pipe leads to the cushion, which is so formed that all cushion elements are connected with each other through the pipes and the valve housing in every condition. The cushion elements can be jointly and simultaneously connected through the valve to a compressed air source.
This seat cushion has a considerable disadvantage: As is known, lengthy sitting in one and the same position leads to pronounced fatigue, as well as also to disturbances in blood circulation especially in the legs. Therefore, after some time, every seated person changes position quite spontaneously, and thereby his seated position. A prerequisite for substantially fatigue-free sitting, however, is the necessity that the body be effectively supported which, however, is the case only to a very limited extent according to the British Pat. No. 486,985, since, as a result of the fact that all cushion elements always communicate with each other, the seat cushion surface yields all over and therefore is not in a position to brace the body of the seated person, so that at all times a considerable amount of muscular exertion is required to hold a certain seated position.
This disadvantage does not arise in other known seating equipment with more or less unyielding cushions of a certain form, but these cushions obviously are capable of optimally supporting the body of a seated person only in a certain seated position, since they cannot adapt to other seated positions.
In this connection, it should be noted that the formulation that the cushion elements be exclusively connectable with one another through the pipes, naturally does not mean that they are not also connectable to a compressed air source or the like, but rather it is only to be stated that in one position of the valve or valves only a connection of the cushion elements with one another takes place and not simultaneously also a connection to the compressed air source or the like.
This is important in view of U.S. Pat. No. 2,938,570 which describes an armchair, the seat and back rest cushion of which is built up of inflatable cushion elements. For this purpose, a pipe leads from each cushion element to a valve that is connected to a compressed air source. According to the position of this valve, the connection between all cushion elements and the compressed air is interrupted, or one, several or all cushion elements are connected to the compressed air source, in which case they naturally are also connected to each other. In this known armchair, however, the cushion elements do not form a grid but form flat elements superposed in a direction perpendicular to the cushion plane, since the purpose of this known construction consists only in shifting the body position of a seated person in a direction perpendicular to the cushion plane by inflating the cushion elements do a greater or lesser degree. This known armchair is therefore not comparable with the chair or armchair according to the invention, neither from the standpoint of the problem to be solved nor in view of its structural configuration, since, as mentioned, the cushion elements do not form a grid and moreover they are always also connected to a compressed air source when they are connected with each other through the said valve.
Finally, from German publication for opposition (DT-AS) 1,296,761 seating equipment is known, the back rest cushion of which is composed of inflatable cushion elements extending laterally. Furthermore, an additional inflatable cushion element which likewise extends laterally and rises obliquely upwards and backwards is arranged at the back part of the seat cushion for straightening the spine. The remaining portion of the seat cushion is free of cushion elements. Aside from the fact that in this seating equipment also the cushion elements do not form a grid and as a result the cushion cannot optimally adapt to various sitting positions, it is also impossible in this known seating equipment to arrive by a certain valve positioning at a state in which by altering the seating position air is displaced from one cushion element to another and that this distribution of the cushion medium can be maintained.
Any flowable medium may be used as the cushion medium, i.e. air, any other gas, or a more or less viscous fluid.
It is also conceivable to apply the basic conception of the invention to other seating equipment which has only a seat cushion or a seat cushion in combination with a not especially cushioned back. In the same way, the invention may also be applied for reclining and sleeping. Preferably, office chairs and automobile seats will be constructed according to the invention.